1. Field of the Invention
The present invention relates to an archery broadhead and more particularly to an improved broadhead having adjustable blade retention and replaceable blade elements.
2. Description of Related Art
Many types of arrows are known and available for shooting with an archer""s bow. An archer""s choice of a particular arrow depends on the intended activity or use for the arrow. For example, arrows used for competitive target shooting generally differ from those used for hunting.
The sport of archery includes activities ranging from target practice to game hunting, and the art of providing arrows suitable for each of these purposes has become highly developed. Many types of arrowheads have been designed to serve a particular purpose, each having specific operating characteristics. Thus, arrowheads specifically intended for hunting large, thick-skinned, heavy-boned game such as bear have been advanced as well as those with heads particularly suitable for hunting large, thinner-skinned, lighter-boned game such as deer. Arrowheads also have been developed for hunting fowl, particularly turkey, for hunting squirrels and other small game, and for bow fishing.
Arrows used for hunting typically comprise an arrow shaft and an arrowhead commonly referred to as a broadhead. The broadhead is mounted at a tip end of the arrow shaft opposite an arrow string engaging nock. Conventional broadheads typically comprise a central ferrule that mounts a plurality of broadhead blade elements, each blade element presenting an inclined, razor sharp edge. Broadheads are designed for the purpose of striking and piercing a target, such as a game animal, and consequently the blades are designed to inflict a wound exhibiting profuse bleeding.
Broadhead blade elements typically resemble triangularly shaped razor blades. Two or more blade elements are mounted in longitudinally extending slots formed in the broadhead ferrule. The blades can be fixedly secured in the ferrule slots by several means.
Broadheads are easily damaged during use. The blade elements, and particularly the razor sharp edge defined along portions of the blade element, are susceptible to damage due to missed shots or when the archer makes his shot but the broadhead strikes a large bone of a game animal. If a shot is missed the broadhead may strike rocks or other hard objects that break the blade element or cause severe nicks in the blades"" sharpened edges. Even when the arrow hits its mark, the broadhead may hit a large bone causing the blade elements to break. This usually occurs when the broadhead hits the large bone obliquely and glances off the bone thereby imparting most of the impact energy along one blade element.
One consequence of broken blade elements is that the arrow cannot be used until the broadhead is repaired. This is so because a broadhead with broken and/or missing blade elements are statically and aerodynamically unbalanced. This unbalanced condition prevents a launched arrow from traveling the intended and predictable trajectory. Also, if the arrow with a damaged broadhead does hit its mark, the broadhead may not inflict the type or quality of wound that is humanely desired by bow hunters.
When such a broadhead is attached to the arrow shaft in non-releasable fashion, it is necessary for the archer to have a wide range of arrows, some for target shooting, some for hunting larger game and some for smaller game. Arrows having interchangeable heads were developed in an effort to reduce the number of arrow shafts which might be required, as in U.S. Pat. No. 2,289,284 to Chandler and U.S. Pat. No. 3,910,579 to Sprandel, but such approaches require replacement of the entire broadhead, and therefore have the drawback that a new complete broadhead must be manufactured for each intended use.
Arrowheads with interchangeable blades also have been developed in an effort to increase the versatility of the arrowhead. Systems typical of this general approach are disclosed in U.S. Pat. No. 2,940,758 to Richter, U.S. Pat. No. 4,036,479 to Sherwin, and U.S. Pat. No. 4,146,226 to Sorenson. Such systems generally employ a plurality of independent blades each of which can be fitted into a different one of a plurality of slots in the ferrule. Usually, the blades are then clamped by axially-acting clamp members which are separate from the arrowhead body, or the body itself may act as a clamp member.
U.S. Patent No. 3,741,542 to Karbo and U.S. Pat. No. 4,349,202 to Scott illustrate prior art arrowheads in which blade assemblies comprising two or more blades are releasably secured to the arrowhead body. Though such arrowheads represent a distinct improvement in the art, they have the deficiency that, when the blades are of substantial size, the clamping forces are applied to only a limited portion of the blade; therefore, the blade is likely to fracture or distort under the rigors of use. In other approaches, as in U.S. Pat. No. 3,398,960 to Carroll, a blade structure is positioned over a central shaft and locked thereto, but such approaches have the deficiency that the entire blade structure is external and more easily deformed or loosened on impact. While these prior art proposals have achieved significant acceptance in the trade, there has been a continuing need for improvement, particularly in the ease of assembly of the arrowhead and its ability, once assembled, to withstand the rigors of actual use.
U.S. Pat. No. 4,986,550 to Segovia discloses one means for fixedly securing blade elements in a broadhead. Segovia shows a broadhead comprising an arrowhead body or ferrule with longitudinally extending, radially oriented slots for accepting corresponding blade elements. Each blade element includes a central flange from which a sharpened blade extends. The blade flanges have acutely shaped projections at opposing ends. As shown in FIG. 1 of Segovia, one projection fits captively within a cooperating portion of the slot and the other projection is engaged by a cooperating washer, which, when compressed against the ferrule, fixedly secures the blade unit in the slot.
Another blade element securing means is shown in U.S. Pat. No. 4,210,330 to Kosbab. Kosbab shows, in FIG. 2 thereof, a modular broadhead having a central ferrule with blade engaging slots radially offset from the central axis of the ferrule in planes parallel to planes tangent to the peripheral surface of the ferrule. Each blade includes opposed acute angle projections that cooperate, at one end of the blade, with an annular groove formed in a tip that threaded engages the ferrule and, at the opposed end of the blade, with a ferrule collar. The engagement of the tip and ferrule collar with the acute angle projections secures the blade in captive engagement with the ferrule.
U.S. Pat. No. 5,482,294 to Sullivan et al. discloses an archery""s broadhead having a longitudinally extending ferrule with a plurality of blade elements mounted by and extending from the ferrule. A securing flange extends from the blade body and extends through a ferrule slot into a ferrule cavity. An engaging bar is disposed in the ferrule cavity and engages portions of the securing flange of the blade element. Yet, the Sullivan et al. broadhead has several shortcomings.
As shown in FIGS. 5a-10 of Sullivan et al., the angular space between the outer surface of the engaging bar and the inner surface of the ferrule remains substantially empty upon broadhead assembly. While this configuration may provide a somewhat lighter broadhead, the broadhead assembly as a whole, including the blade elements and ferrule, provides suspect strength upon impact. Upon impact, the blade elements of a broadhead are exposed to significant longitudinal stresses along the length of the broadhead. The Sullivan et al. broadhead arrangement provides only a small surface area contact between the blade elements and the ferrule in a longitudinal configuration, detailing a second disadvantage to this broadhead. The securing flange 72 is truncated adjacent an arcuate side edge 84 which seats into the arcuate portion 62 of the slot 60 when the broadhead assembly 10 is assembled. The arcuate side edge 84 is undercut relative to the securing flange 72, forming a notch 86 which, when the blade 18 is seated into engagement with the ferrule 16, engages the blade support edge 64 of the ferrule 16. The notch 86 seated in support edge 64 only provides a minimum amount of protection to the blade element upon impact. Further, the alignment shoulder 34 of ferrule 16 simply provides alignment of the longitudinal axes of the broadhead assembly 10 and arrow shaft 14. The alignment shoulder is integral with the ferrule and cannot be adjusted longitudinally to further the snug fit of blade elements in the broadhead.
Therefore it can be seen that there is a need in the art for an archery broadhead having replaceable blade elements with adjustable blade retention.
Briefly described, in its preferred form, the present invention comprises a broadhead including blade elements, a mandrel having an adjustable collar, a ferrule and a tip. The present broadhead overcomes the deficiencies in the prior art by providing an archery broadhead having adjustable blade retention and replaceable blade elements that are mechanically and captively engaged: first, between the arrowhead tip and the collar which is in communication with the broadhead mandrel, the tip and collar sandwiching the blades therebetween, limiting longitudinal movement of the blade elements; second, by ferrule slots from which the blades protrude through the ferrule, limiting rotational movement of the blade elements; and third, by removing any void space between the outer surface of the mandrel and the inner surface of the ferrule.
The present invention is an archer""s broadhead having blade elements supported by a mandrel preferably disposed in a longitudinally extending ferrule. Each blade element defines a generally triangularly shaped blade body having a sharpened blade edge, which sharpened blade edge extends from a ferrule slot. A mandrel engaging portion of the blade extends from the mandrel edge of the blade body distal from the sharpened blade edge. The mandrel engaging portion can be a flange portion angularly displaced from the blade body. Alternatively, the mandrel engaging portion can be a loop extending from the mandrel edge.
The flange portion of the blade can extend substantially the entire length of the blade body, or can extend only a portion of the length of the blade. The flange portion also can extend arcuately from the blade body in varying arc lengths. The flange portion of the blade elements are designed to keep the blades in vertical alignment and in surface contact with the mandrel. The flange portion preferably xe2x80x9csnapsxe2x80x9d around an arcuate portion of the outer surface of the mandrel, locking the blade elements in position along the mandrel. Alternatively, blades with loops are retained by the mandrel via the loops through which the mandrel extends.
The mandrel preferably comprises threaded portions and incorporates a collar, which collar is adjustable along the length of the mandrel. The collar is designed as a stop supporting the back edge of the flange portion of each blade element, or supporting the back surface of the loop of the bottom blade element, which loop of the bottom blade element in turn supports the next highest loop of next blade element, and so on. This arrangement further secures the blades from longitudinal movement along the length of the mandrel.
The collar of the mandrel comprises a hard material, supports a substantial portion of the weight of the blade elements, and provides a stop against the longitudinal stresses borne by the blade elements upon the broadhead striking the target. Without the collar, the blade elements typically deform the ferrule body upon impact, thus necessitating replacement of the ferrule. Compounding this problem, the blade itself may also fail, requiring replacement. The present collar lessens such component failure. The hard material forming the collar is defined as a material that will support the impact of the blades upon striking the target without significant deformation to the collar. For example, conventional broadhead constructions support blade elements against an aluminum ferrule, which aluminum ferrule easily deforms upon blade contact with the target. The present invention rests portions of the blades against a collar made of, for example, steel, that can sustain blade impact without significant structural damage. Therefore, if a blade is damaged upon contact, the collar prevents damage to the ferrule and one only need replace the damaged blade element.
The collar of the mandrel is preferably rotationally secured to the bottom portion of the mandrel by threading so the collar can be adjusted vertically along the length of the mandrel, providing secure locking of the blade positions between the collar and the arrow tip. This arrangement provides a level of securing and alignment not achieved in conventional broadhead assemblies. Alternatively, the collar can be formed as an integral part of the bottom portion of the mandrel and the tip adjusted downward along the length of the top portion of the mandrel. In yet another embodiment, a collar may be inserted into the ferrule, then the blades, and then the mandrel. This embodiment can be used when the tip is integral with the mandrel.
The ferrule defines a longitudinally extending central cavity and a plurality of ferrule slots extending from and communicating with the central cavity. Upon broadhead assembly, the flange portion (or loop) of the blade is located in the ferrule cavity between the outer surface of the mandrel and the inner surface of the ferrule. The flange portion of the blade element is arcuate to extend around a portion of the outer surface of the mandrel.
The arrowhead tip can engage the top section of the mandrel, the top section of the ferrule, or both, to secure the top of the blade elements and mandrel to the ferrule.
The broadhead fixedly secures to an arrow shaft at a mounting component. Preferably, the mounting component comprises a ferrule extension, which ferrule extension provides a mounting portion adapted to be secured into a bore in the arrow shaft.
In one preferred embodiment, the broadhead comprises three blade elements, each blade element having a flange portion extending from the length of the blade and approximately 120 degrees around the outer surface of the mandrel. In another embodiment, each blade has a full loop extending from one-third the length of the blade, the loop having an inner diameter incrementally larger than the outer surface of the mandrel. In this embodiment, the mandrel slips within the stacked loops. The loop of the bottom blade rests atop the collar of the mandrel. The loop of the middle blade rests atop the loop of the bottom blade, and the loop of the top blade rests atop the loop of the middle blade.
Each blade can comprise more than one flange portion or loop, providing each separate flange portion or loop occupies a free portion of the length of the mandrel upon assembly of the broadhead. For example, if each blade incorporates more than one loop, this configuration is somewhat similar to the hinge of a door wherein the hinge panels are the blade elements having loops, and the pin is the mandrel.
In another preferred embodiment, each blade element can comprise flange portions running the length of the blade and extending incrementally less than 360/n degrees around the outer surface of the mandrel, where n equals the number of blade elements comprising the broadhead. In this embodiment, the back edge of each flange portion of each blade element rests atop a portion of the top surface of the collar.
In yet another preferred embodiment, the present broadhead assembly can comprise blade elements, a mandrel having an adjustable collar, a circumferential locking assembly and a tip. In this embodiment, the mandrel engaging portions of the blade elements are loops. The mandrel extends through the loop of each blade, wherein the assembly comprises at least two blades, a top and a bottom blade, where the loop of the bottom blade rests atop the collar. The circumferential locking assembly locks the blade elements from rotating individually, so if the blade elements rotate around the mandrel, they rotate as a single unit. The locking assembly can further lock the unity of blade elements from shifting circumferentially around the mandrel once the blades have been placed in proper alignment upon construction of the broadhead. Since the loops of the blades lay one atop another, and since the blades are secured from sliding on the mandrel both circumferentially (by the locking assembly) and lengthwise (by compression between the collar and the tip), this embodiment does not require a ferrule.
It will be appreciated that the present invention may be carried out with the elements forming the present broadhead constructed of various materials. Accordingly, wood, metal or plastics may be utilized and the latter may include glass fiber reinforced plastics. Quite obviously, these elements can be formed of any other suitable material exhibiting sufficient dimensional stability for use in this environment.
The broadhead of the present invention provides numerous advantages over conventional broadhead designs. For example, the broadhead of U.S. Pat. No. 5,482,294 to Sullivan et al. provides a blade support assembly wherein an arcuate side edge of the blade is undercut relative to a securing flange, forming a notch which, when the blade element is seated into engagement with a ferrule, engages the blade support edge with the ferrule. As shown in FIG. 4 of Sullivan et al., the notch 86 supports the blade element in the direction opposite the direction of broadhead travel. See also FIGS. 1, 2a and 2b. As shown, notch 86 provides little structural support for the blade element in this direction. Thus, when the Sullivan et al. broadhead strikes its target, the blade element typically fails at a site in proximity to notch 86.
Unlike the Sullivan et al. broadhead, the present broadhead provides a blade support assembly wherein preferably a substantial portion of the blade body is supported both longitudinally along a portion of the length of the blade, and tangentially along a flange portion or loop.
Thus, it is an object of the present invention to provide an improved archer""s broadhead.
It is a further object of the present invention to provide a broadhead having blades that are replaceable and interchangeable.
It is another object of the present invention to provide a broadhead in which the blade elements are mechanically secured to the mandrel along substantially the entire length of a flange portion of the blade element.
It is another object of the present invention to provide a broadhead with a mandrel having an adjustable collar.
Another object of the present invention is to provide a blade assembly that better supports each blade from longitudinal stresses when the broadhead hits its target.
These and other objects, features and advantages of the present invention will become more apparent upon reading the following specification in conjunction with the accompanying drawing figures.